The invention relates to an interlock device between an ignition key lock and a manual selector lever of an automatic gear-change transmission, in which a detent cam of a camshaft part is rotatable by an ignition key acting counter to a resilient bias and mounted in alignment with and rotatable relative to the axis of rotation of the ignition key lock. The detent cam interacts with a first latch element which is displacably arranged on a housing part, fixed in terms of movement relative to the ignition key lock housing, and is connected kinematically to a rod end of a mechanical adjusting linkage. Another rod end of the linkage is connected kinematically to a further latch element pivotably mounted, on a housing part fixed to the vehicle in the vicinity of the manual selector lever. The other end acts with a second detent cam, (moveable by the selection of movements of the manual selector lever) through counterdetent means. When the manual selector lever is actuable into a parking position and the ignition lock is brought into a one set rotary angle position (position of rest), the ignition key can be inserted and withdrawn from the ignition key lock lock. The mutual relationship of the two detent cams and latch elements is such that only in the parking position of the manual selector lever can the ignition key lock be brought into the position of rest and in that position of rest, the manual selector lever is necessarily locked in its parking position. The second detent cam of the manual selector lever is uncoupled from the counterdetent means of the further pivotable latch element when the manual selector lever is not in the parking position. Second resilient means, supported relative to the housing, act with an uncoupling effect to disengage the second pivotable latch element from the second detent means.
An interlock device of this general type is known from German Offenlegungsschrift No. 3,425,189. There an additional flat intermediate slide is mounted in the steering-column lock housing so as to be displacable between two end positions and in a plane perpendicular relative to the axis of rotation of the ignition lock. The slide is actuable into one end position by a detent cam of a camshaft part arranged in alignment with and rotatively fixed relative to a lock-cylinder core when an orifice of a displacable latch element, connected to a linkage, is brought in alignment with the path of movement of a detent pin of the intermediate slide. This occurs in the parking position of the manual selector lever, so that the detent pin can then enter the orifice and the intermediate slide can assume the respective end position, in which the camshaft part is brought into its rotary angle position corresponding to the position of rest of the ignition lock. Then the ignition key can be removed. When the ignition lock is re-actuated into the driving position, the intermediate slide is actuated into the other end position by resilient means and it penetrates into a circumferential groove of the camshaft part and in an end position rests against the groove bottom. In this end position, the detent pin of the intermediate slide has come out of the orifice of the displacable latch element, so that the manual selector lever is now actuable out of the parking position, which hitherto now has been blocked by the detent pin into its other selection positions. In these other positions, an actuation of the ignition key into the position of rest is blocked because the orifice of the displacable latch element no longer coincides with the detent pin of the intermediate slide and hence the latter is fixed essentially immovably in its end position on the groove bottom of the camshaft part.
In this known interlock device, there is the danger as a result of a breakage of the mechanical adjusting linkage, that the position of rest of the ignition lock will be blocked and therefore it will no longer be possible to remove the ignition key and consequently stop the engine. The reason for this is that it is not possible to actuate the mechanical adjusting linkage from the camshaft part, i.e. by means of the ignition key. Here the intermediate slide is constantly actuated by one resilient means with the effect of blocking of the position of rest and the displacable latch element is actuated by the other resilient means with a blocking effect for the intermediate slide.
An interlock device of a different type between an ignition lock and a steering shaft and using a two-part longitudinal displacable detent latch, is known from European Patent Specification No. 0,082,323. One part of the detent latch is made bolt-shaped and is engagable into a corresponding recess of the steering shaft. The orifice of the other detent-latch part is designed as a frame-shaped slide and has a camshaft part arranged both in alignment with and rotational fixedly relative to the lock-cylinder core of the ignition lock and passing through it. Nevertheless, this camshaft part does not interact with its detent cam directly, but rather, via a second frame-shaped slide on a detent latch, which is actuable by a resilient means supported on the housing, into the detent position blocking the steering shaft.
The object on which the instant invention is based is to essentially provide an interlock device that will avoid the danger that, a position of rest of the ignition lock will be blocked as a result of breakage of the mechanical adjusting linkage and thus the ignition cannot be turned off.
According to the invention, the object is achieved in an advantageous way by having a camshaft part with its axis of rotation aligned with an orifice of a frame-shaped slide of a displacable latch element and wherein an additional control cam can be brought into engagement via its detent cam with a counterdetent cam and via its control cam with a counter control cam. The counterdetent cam and counter control cam are arranged to extend radially relative to the axis of rotation of the camshaft part and at points of the slide located diametrically opposite one another in relation to the camshaft part. In this way the counterdetent cam is located at a differential angle of rotation in front of the rotary angle position, corresponding to the position of rest of the detent cam of the camshaft part. The counter detent cam can be brought out of engagement with the detent cam of the camshaft part by resilient means counteracting the actuation by the ignition key. This resilient means is designed with a higher spring force than a resilient means acting on the pivotable latch element associated with the annular selection lever and with the effect of uncoupling the detent cam from the manual selector lever. During actuation into the rotary angle position, corresponding to the driving position of the ignition lock, the control cam of the camshaft part comes into engagement with the counter control cam in such a way that the counterdetent cam of the slide is located in the path of movement of the detent cam of the camshaft part and the pivotable latch element is uncoupled from the detent cam of the manual selector lever.
In the interlock device according to the invention, the detent cam of the camshaft part and the associated counterdetent cam of the frame-shaped slide are necessarily brought out of engagement by the respective resilient means, should the mechanical adjusting linkage be broken such as might occur in the event of an accident.
According to the invention, there is advantageously no need for the intermediate slide necessary in the known interlock device.
In the known interlock devices, when the parking position is assumed, the bolt-shaped detent cam of the manual selector lever enters a fork-shaped counterdetent member on the pivotable latch element, which is actuable into one of two end positions by means of a torsion spring supported on the housing. In this first end position, the fork-shaped counterdetent member is open towards a notch orifice of a notch plate fixed relative to the housing, for the engagement of the positions of the selector lever. When the gear selection lever leaves the parking position, the detent cam (belonging to the manual selector lever and also used as a resilient counter notch) can come out of the fork-shaped counterdetent member and change over to that region of the notch orifice not coinciding with the counterdetent member. When the parking position is selected, the pivotable latch element is actuated by the detent cam into its other end position, in which the fork-shaped counterdetent member coincides with the notch associated with the parking position and is closed off from the remaining part of the notch orifice by one of its fork arms.
In this known interlock device, there is the danger that after a breakage of the torsion spring, the pivotable latch element will be shiftable into the end position last described, if the manual selector lever is not in the parking position. Under these circumstances, the selection of the parking position would be blocked by the said fork arm of the counterdetent member.
In the interlock device according to the invention, this danger is avoided by providing a control cam on the manual selector lever and a corresponding counter control cam on the second pivotable latch element, in such a way that engagement of these cams in a selection position of the manual selector lever which does not correspond to the parking position, prevents an actuation of the counterdetent cam of the slide (by the adjusting linkage) into a position not located in the path of movement of the first detent cam of the camshaft part.
It is also advantageous if the frame-shaped slide is displaceably mounted on an end face of a cylindrical switch housing, mounted fixably in terms of movement in the ignition-lock housing and adjacent to the lock-cylinder core. The camshaft part can have a hub which is central relative to the axis of rotation of the ignition lock and which is fixed in terms of rotation on an end of a controller which is mounted rotatably in the switch housing and projects therefrom. The camshaft part can be connected to the lock-cylinder core by means of a plug coupling. Also the camshaft part can consist of plastic and be reinforced with a metal driving plate on its end face confronting the lock-cylinder core.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.